Error Details: The Jetpack server could not communicate with your site’s XML-RPC URL. Please check to make sure http://yoursite.com/xmlrpc.php is working properly. It should show ‘XMLâ€‘RPC server accepts POST requests only.’ on a line by itself when viewed in a browser and should not have any blank links or extra output anywhere.

The URL request that’s being made and fails is: http://yoursite.com/wp-admin/admin.php?page=jetpack&action=register&_wpnonce=********** where ********** represents an alphanumerical code cooked up by Jetpack (like: bf67aebc88)

As many others before me I’ve also run into the jetpack problem mentioned above, however it seemed that none of the solutions I’ve found out there fixed the issue for me, mostly due to the specifics of the server setup, therefore I’ll illustrate below how I’ve fixed the problem for myself, and I’ll also provide some links to additional resources that have worked for others (for users who are mostly having to do with shared hosting environments).

Additional note: this fix also works for the situation in which you’re trying to use the WordPress for Android mobile app and your’re trying to add your self hosted blog to the android app – which fails without the steps below. Just as in the case of the Jetpack fix, this only has to be done once, so you might consider activating Jetpack and adding your self hosted blog to the android app at the same time as to not have to repeat the steps below.

If you are unfamiliar with LEMP (Linux server using Varnish, Nginx, W3 Total Cache, and WordPress), have a look at this post to get started.
In the this setup combination the culprit is actually Varnish which seems that although is passing through the request to the nginx backend (a.k.a no cache), some of the .js scripts required by Jetpack are not loaded/executed but rather served from the Varnish cache, leaving the jetpack plugin with incomplete data while attempting the request.
To fix this we could go ahead and blow our brains out trying to tweak the varnish configuration .vcl file to properly handle the request, but given that this Jetpack activation is a one time thing we’ll just go ninja, do it faster and with very little downtime.

Step 1:

Open the nginx configuration file specific for your site:

nano /etc/nginx/conf.d/yoursite.conf

edit and change the listening port to port 80. Typically nginx would be listening on a specific port (like 8080) for requests from varnish (which would be listening on 80).

listen 80;

save and exit the file:

Ctrl+x > y > Enter

Step 2:

Now that we’ve changes nginx listening port to 80, before we can reload the configuration for the changes to take effect, we must stop the Varnish webserver, and we do that by issuing the following command:

service varnish stop

Step 3:

With the Varnish server stopped it is not time to reload the nginx configuration for the webserver and we do that by issuing the following command:

service nginx reload

Step 4:

What’s happening now is that all wordpress requests are handled by nginx directly and are no longer passing through the Varnish caching layer.
Now go back in you wordpress blog, and click on the Jetpack tab > Connect to WordPress.com > Authorize Jetpack and voila…Jetpack has been authorized and enabled for your blog.

Note: as mentioned above, now would be a good time to also add your self hosted blog to the WordPress for Android mobile app to avoid having to redo these steps.

Step 5:

It is now time to undo what we did above with nginx and varnish in order to re-enable the varnish caching layer (don’t worry, only the activation had issue, everything else works well with varnish cache in front of it).

Open the nginx configuration file specific for your site:

nano /etc/nginx/conf.d/yousite.conf

Edit and change the listening port back to it’s original value (from 80 to 8080)

listen 8080;

Save and exit the file:

Ctrl+x > y > Enter

Reload the nginx web server configuration for changes to take effect

service nginx reload

Finally, it’s time to restart varnish cache:

service varnish start

Now it’s time to go back to your blog and play around with Jetpack as much as you want. You’ll find that pretty much everything works and you can enable and disable the various available modules, and you can even disconnect from WordPress.com if you want to, with no problemâ€¦.however should you want the re-enable it, you’ll need to perform the above steps all over again.

Conclusion: the fix is rather simple actually, and if you read through the guide before actually doing it, it will take you less than a minute to complete, and with basically no downtime since you’re disabling varnish, but immediately enabling nginx as the fallback. This way, I think, is better than adding rules to the varnish configuration, since it’s something you only have to do it once, and just as the guide above it would still require you to stop and restart varnish.

Notes:

Look at the common issues as depicted on the jetpack.me site: http://jetpack.me/troubleshooting/troubleshooting-tips/

Look at the plugin compatibility know issues on the jetpack.me site: http://jetpack.me/troubleshooting/known-issues/

Try the “XML-RPC De-whitespacer” http://wordpress.org/extend/plugins/xml-rpc-de-whitespacer/ plugin in order to remove any white spaces / empty lines from your themes and plugins.

If you’re running lighttpd instead of nginx/varnish, you should check out this post on how to fix jetpack connection issue.

If none of the solution above resolve your xml_rpc 32700 glitch, you can contact the Jetpack.me guys using this link: http://en.support.wordpress.com/contact/?jetpack=needs-service, but before you do it would help you and the jetpack guys if you:

Not sure if an update changed things, but this doesn’t work for me. I’m running this exact setup (I am running php 7, but don’t think that’s an issue).

However, I do not have the “nano /etc/nginx/conf.d/yousite.conf” file.

Also, tried adding the “if (req.url ~ “wp-(login|admin)|preview=true|xmlrpc.php|minify.php”) { return (pass); }”, but couldn’t get it to work. I’m still learning, so maybe I didn’t put it in the right spot? I get an error when starting the service.